The present invention generally relates to machinery for cutting and shredding vegetation by the use of double-shredding action effected by dual counterrotating blade assemblies. More particularly, the invention is a rotary cutter apparatus which cuts and shreds by blades, some of which rotate in a clockwise direction and others in a counterclockwise direction, and that is particularly designed for cutting down and shredding post-harvest stubble, for clearing fields of coarse vegetation, for mowing and mulching grassy areas, and the like. The invention finds special application in connection with wide-swathed agricultural and commercial rotary cutting equipment.
Rotary cutters are well-known in the agricultural industry. They can vary in size and type including single deck equipment, multiple deck equipment, and equipment having decks that can be tilted up and down for cutting on large contoured fields, for example. Typically, this equipment is pulled by a pulling vehicle such as a tractor and is driven by the power take-off (PTO) shaft of the pulling vehicle. Rotary cutters are especially designed for rugged, heavy-duty use and can often accommodate and cut numerous types of vegetation including thick-stalked plants, saplings, small diameter trees, and the like. Rotary cutters are available in various types and sizes for handling various cutting tasks from general pasture clipping to farm and commercial operations. Often, these are heavy-duty machines built for long hours of rugged cutting.
Present day commercial rotary cutters have either a single blade assembly or have multiple blade assemblies that do not lie along coinciding axes of rotation. Generally speaking, these cutters achieve good cutting results insofar as they sever the vegetation to cut it down. However, this traditional approach has limited effectiveness in shredding the vegetation during the cutting operation. Under many conditions, the cut vegetation passes out of and behind the rotary cutter in large clumps or elongated pieces. The final result can be a cut path that is slow to decompose because of the elongated size and density of the severed vegetation. While some shredding action can occur in order to speed decomposition of the cut vegetation, its effectiveness is limited and adversely affected by vegetation size and type and by cutting conditions.
It has been proposed to provide a rotary cutter having double counterrotating blades in order to attempt to achieve a double-shredding action by the rotary cutter. Objectives include promoting more rapid decomposition, destruction of insects such as boll weevils, corn bores and the like, while improving evenness of spreading for reducing windrowing of the cut vegetation. Such a proposed structure is found in U.S. Pat. No. 3,385,043 to Seymore.
The gearbox and drive train assembly disclosed by the Seymore patent has been found to exhibit defects that seriously impair the mechanical viability, repairability, maintenance and serviceability of the gearbox and drive train. In addition, this proposed cutter requires difficult machining procedures and is very susceptible to misalignment of bearing assemblies, leading to significant reduction in bearing life. For example, the Seymore patent teaches that its center shaft is supported by three bearing assemblies, and they are of the tapered roller bearing type. This entails close machining procedures and tight tolerances and generally complicates and substantially increases the difficulty of adjustment for proper bearing alignment. Also, certain components are welded or force-fit together, which eliminates or seriously restricts adjustability, while also creating situations in which entire assemblies must be replaced because the assemblies cannot be readily disassembled without serious damage to or misalignment of component parts. It will be appreciated that misalignment of and/or damage to drive train components that rotate at a relatively high speed will be detrimental to the equipment, including noise development and working life reduction.
It has been found that, by the improvements embodied in the present invention, these shortcomings and difficulties of units such as those disclosed in the Seymore patent are virtually avoided while still achieving the advantageous objectives that are specified in the Seymore patent with respect to providing double shredding action by co-axial double counterrotating blades.
In summary, the present invention effects these improvements by providing a rotary cutter having at least one deck assembly which supports and houses a gearbox drive assembly for driving both an upper blade assembly and a lower blade assembly which counterrotate with respect to each other along the same axis of rotation in order to achieve the shredding action that is characteristic of the present invention. The blade gearbox drive assembly includes a rotatably mounted drive output shaft which drives the lower blade assembly. Also included is a rotatably mounted driven output tube for driving the upper blade assembly and for receiving the output shaft that passes through the output tube. Only two bearing assemblies mount the output shaft, and these two bearing assemblies preferably are not tapered bearing assemblies. Preferably, the output tube is removably attached to the gearbox drive gear for the upper blade assembly in order to ensure that both the output tube and the drive gear are replaceable without damage to the other. It is also preferred that the drive tube and the upper blade assembly are removably secured to one another.
It is a general object of the present invention to provide an improved rotary cutter with counterrotation gearbox and blade drive assembly.
Another object of this invention is to provide an improved rotary cutter counterrotation gearbox that prevents misalignment of bearings and side loading of drive shafts, while improving bearing life.
Another object of the present invention is to provide an improved rotary cutter counterrotation gearbox that facilitates assembly and serviceability and that avoids situations leading to component damage when disassembly and/or service are required.
Another object of the present invention is to provide an improved rotary cutter having counterrotating dual blade assemblies and including an easy attachment blade assembly for facilitating servicing, repair or replacement of the blade assembly or of its blades.
These and other objects, features and advantages of the present invention will be clearly understood through a consideration of the following detailed description.